unit 2 hths 1110 weber

Which unit of matter retains properties and characteristics of the element?

an atom

What are elements?

Substances with different chemical properties.

What is found in the nucleus of the atom?

neutrons and protons

What is one unit of atomic mass?

1 AMU or Dalton.

What are the 4 most common elements in the human body?

Oxygen, Carbon, Hydrogen, and Nitrogen

List the order of the most common elements as they are found in the human body from greatest to least.

O, C, H, N

What is the mass of neutrons?

1 Dalton

What is the mass of protons?

1 Dalton

What is the mass of electrons?

very little mass, almost 0.

What does the electron occupy?

A probability cloud.

According to Heisenberg, what do we not know about atoms?

We can know either its position or momentum, but not both.

Energy is _______ on the inner levels on the electron shell, and _______ on the outer levels of the electron shells.

lower, higher.

What are the orbitals of an atom?

s, p, d, f

What are photons?

Both a particle and a wave that represent excess energy an atom is trying to shed.

Do photons have mass?

Almost none.

What is the law of conservation of energy?

Energy cannot be created or destroyed

Where do photons come from?

The rearrangement of nuclei, nuclear fission, electron rearrangement.

What is nuclear rearrangement?

P and N rearrange themselves in a lower-energy configuration, the leftover energy is released as a photon.

What is the order of visible light? Wavelength and energy?

(long wave length, least energy, low frequency) red, orange, yellow, green, blue, indigo, violet (short wavelength, most energy, high frequency)

List the types of radiation in order from highest to lowest frequency

high-gamma rays, X-rays, ultraviolet radiation, visible light, infrared radiation, and radio waves.-low

What is an isotope?

Different elements having same numbers of protons, different numbers of neutrons.

What is the atomic number?

The number of protons in an atom

Hydrogen always has _____ proton

one

What are the forms of radiation?

Alpha particles, beta particles and positrons

What are alpha particles?

They are a helium nuclei with 2 protons and 2 neutrons.

What are radioisotopes?

Isotopes that are unstable and emit radiation.

What are beta particles?

Electrons with a negative charge

What are positrons?

Antimatter electrons with the same mass but opposite charges.

Describe electron capture.

An electron strikes thee nucleus and is absorbed, resulting in the emission of X rays. Can penetrate human tissue.

Describe gamma emission.

Release of a photon of even higher energy than an X ray photon.

Describe spontaneous fission.

How nuclear bombs produce energy.

What are alpha particles penetration ability and what are they stopped by?

Very little penetrating ability. Stopped by paper.

What are beta particles stoped by?

Aluminum.

What is the penetration ability of gamma particles and what can they penetrate?

Greater penetration. They penetrate deeply into tissue. Used to destroy cancerous tissue.

Which subatomic particle participates in chemical reactions?

electrons

What is the electron spin?

Spin can be up and down,

Orbital filling rule:

all ups are filled first, then pairs formed. in remaining parking spots.

Atoms are trying to be like _________.

Noble gases.

H

Hydrogen

Li

Lithium

Be

Beryllium

Na

Sodium

Mg

Magnesium

K

Potassium

Ca

Calcium

Fe

iron

B

Boron

Al

Aluminum

C

Carbon

Si

Silicon

N

Nitrogen

P

Phosphorus

O

Oxygen

S

Sulfur

F

Flourine

Cl

Chlorine

He

Helium

Ne

Neon

Ar

Argon

Kr

Krypton

Xe

Xenon

I

Iodine

Br

Bromine

Se

Selenium

What gives atoms their chemical properties?

Valence Electrons.

The _________ metals have a single electron in the top shells.

Alkali (Li, Na, K)

What is the valence electron?

an electron that is in the highest occupied energy level of an atom, outer most shell.

What are the noble gases?

Helium, Neon, Argon, Krypton, Xenon, Radon

In ________ gases, the __________ available orbitals are filled.

Noble, lowest

How do atoms that are not noble gases achieve low energy state when they have a valence electron?

Sharing, giving, or taking electrons.

What is electronegativity?

Electron pulling capacity of an atom. Increases chemical reactions.

Which are the most electronegative elements in order form greatest to least?

F, O, Cl, N, Br, S

How does electronegativity increase on the periodic table of elements?

Left to right.

K to Ca to Se to Br, how does electronegativity change?

It increases.

Which elements don't participate in chemistry? Why?

Valence electrons, they don't need additional electrons.

What is the atomic number?

the number of protons in an atom

What is the atomic mass?

The weighted average of atomic masses of all naturally occurring isotopes.

What are covalent bonds?

FHa chemical bond that involves the sharing of electron pairs between atoms

Endothermic reaction

A reaction in which energy is absorbed, the energy of products is treater than the energy of reactants

Exothermic reaction

A reaction that releases energy, the energy of the products is less than the energy of the reactants.

How many electrons are shared in double covalent bonds?

4.

How many electrons are shared in single covalent bonds?

2

Polar covalent bonds

unequal sharing of electrons

Ionic bonds

When there is a large difference in electronegativity.

Are ionic bonds strong or weak?

weak

If there is no difference in electronegativity then what type of bond is formed?

Non polar covalent.

What is a hydrogen bond?

a weak bond between two partially charged atoms

What kind of bond does water molecules have?

Polar Covalent bonds. There is an unequal sharing of electrons.

what is a dipole?

A molecule that has two poles

What is an acid?

proton donor (donates a hydrogen ion)

What is a base?

Proton acceptors.

What are examples of bases?

Hydroxyl groups, amino groups, bicarbonate ions.

Acids and Bases can be ______ or ______

weak or strong

Weak acids are acids that only donate a ______ or protons

small

What re strong acids?

Acids that donate all of their protons.

Strong acids completely __________ in water

Dissociate

Strong bases completely ____________ in water

dissociate

What is pH

the measure of a strength of an acid or a base.

What is the pH of water?

7 (neutral)

What is the range on the pH scale?

0-14